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by dknute
Mon Feb 09, 2015 10:33 am
Forum: Troubleshooting
Topic: Why is the PI2 camera-shy ?
Replies: 162
Views: 271916

Re: Why is the PI2 camera-shy ?

Jeez, are there no engineers in this thread? I mean no disrespect to EM testers and other 40-year experience guys but you seem to be more of a theoreticians than anything else. Problem: Pi2 hangs/reboots when subjected to flash. Possibly also high intensity light in general but apparently only sudde...
by dknute
Mon Mar 03, 2014 6:00 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C problems
Replies: 11
Views: 4661

Re: I2C problems

It's the same link I posted earlier :) And, as I've said, it's not really a repeated start if there's a stop in there as well.

I installed WiringPi and now I toggle SDA/SCL lines myself, slowing things down with usleep. Works like a charm. Thanks again, everyone!
by dknute
Mon Mar 03, 2014 11:43 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C problems
Replies: 11
Views: 4661

Re: I2C problems

Many thanks. This will save me a trip to the site :) I read the docs at http://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf and it seems Broadcom Serial Controller (BSC) is not capable of what I want. There is no separate control bit for sending stop condition so I assu...
by dknute
Sun Mar 02, 2014 11:23 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C problems
Replies: 11
Views: 4661

Re: I2C problems

Precisely my problem. I was, however, under the impression that as long as the device address is the same, even a split transaction will happen without any stop conditions. After all, of what use would be I2C_M_NOSTART flag if there were always stops added? And I did find these pages that seem to c...
by dknute
Sat Mar 01, 2014 6:10 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C problems
Replies: 11
Views: 4661

Re: I2C problems

Sorry, can't say what the device is. For now it's a prototype but it might end up being manufactured, in that case I'd be in trouble if I said too much :) I guess I'll have to set up a mirror project somewhere where I can access it, and test I2C with a known, working chip. I just thought it might be...
by dknute
Sat Mar 01, 2014 1:23 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C problems
Replies: 11
Views: 4661

I2C problems

I'm trying to interface RPi with I2C device. It kind of works, but not properly. I'm using ioctl's with I2C_RDWR, rather than read/write since I need to specify internal register address in the device for read/write operation. I've seen some code do that exactly the same way I'm trying and it works,...
by dknute
Wed Jan 16, 2013 1:34 pm
Forum: Troubleshooting
Topic: Unresponsive 3 minutes after boot
Replies: 4
Views: 806

Re: Unresponsive 3 minutes after boot

Might be a faulty Pi but I would check those voltages first, funny things happen when the board is underpowered. Also, I had various problems with one particular SD card that Pi didn't like. Filesystem got trashed each time so I would only get some semi-stable operation on the very first boot and ev...
by dknute
Mon Dec 31, 2012 7:58 pm
Forum: Advanced users
Topic: Updated GPU firmware
Replies: 308
Views: 213924

Re: Updated GPU firmware

smsc95xx.turbo_mode=N performance reduction is about 10-15% or so - the max TCP transfer rate goes down from a bit over 10MB/s to some 8.5MB/s on my LAN. It's probably nothing to worry about for typical network usage (ssh, getting updates) but people who overclock are usually doing it for some perfo...
by dknute
Mon Dec 31, 2012 2:23 pm
Forum: Troubleshooting
Topic: 2012-12-16 Raspbian
Replies: 1
Views: 599

Re: 2012-12-16 Raspbian

Okay, I did some extensive SD card testing and it seems to have developed bad sectors around 2.8GB mark. Somehow these were not detected by Windows format and even worse some of these sectors are not FUBAR, just unstable. This could be why a fresh install failed but only after expandig the filesyste...
by dknute
Sat Dec 29, 2012 11:44 pm
Forum: Troubleshooting
Topic: 2012-12-16 Raspbian
Replies: 1
Views: 599

2012-12-16 Raspbian

So, how many people here are running this particular version? I've been running 2012-10-28, updating it frequently (just the userland though). My Pi had uptime of 25 days and apparently got bored and destroyed filesystem on the SD card. I had it customized with 3 partitions: /boot (60MB FAT), / (3GB...
by dknute
Sat Dec 29, 2012 8:42 am
Forum: Troubleshooting
Topic: Rasberry Pi power off during use
Replies: 20
Views: 2716

Re: Rasberry Pi power off during use

You can either replace F3 fuse or just get rid of it, in which case you'll loose overcurrent protection but quite frankly it's not that important. Pi, on it's own, should never trip it so just be extra careful as to not cause any shorts and you'll be fine. By "get rid" I mean you will need to solder...
by dknute
Sat Dec 22, 2012 9:14 pm
Forum: Troubleshooting
Topic: Raspberry Pi not booting wierd voltage reading
Replies: 11
Views: 1905

Re: Raspberry Pi not booting wierd voltage reading

Replace the battery in your meter :)

As for Pi not booting, the faint light of green LED is usually an indication it wants to boot but something is not right with the SD card (or the image on it). Do you have another card to try with?
by dknute
Fri Dec 21, 2012 4:02 pm
Forum: Troubleshooting
Topic: Why isn't my custom USB data cable working?
Replies: 31
Views: 5574

Re: Why isn't my custom USB data cable working?

Hm, well if it's just the DIN socket and plug you need in between then maybe there is a way to make it work - but as I said before, you'll need some luck to get it working and not dropping the link every few minutes. Anyway, stick to USB cables for data and whatever you have for the power. That mean...
by dknute
Fri Dec 21, 2012 1:23 pm
Forum: Troubleshooting
Topic: Why isn't my custom USB data cable working?
Replies: 31
Views: 5574

Re: Why isn't my custom USB data cable working?

£6? Wow, nasty prices. There's the shipping cost to consider but in general these things should be about 10 times cheaper (if not more but that's for big orders). Anyway, are you trying to create USB data link with "some wire"? You do realize that this is a low voltage, high speed differential trans...
by dknute
Mon Dec 17, 2012 3:24 pm
Forum: Troubleshooting
Topic: RPi doesn't boot after backpowering
Replies: 7
Views: 1212

Re: RPi doesn't boot after backpowering

Too bad about that meter since 0.2 could still be acceptable but 0.4 is not. The way F3 is supposed to work is to either let the current through (without much voltage drop hopefully, hence the low resistance) or pretty much not let it at all when tripped. It's one of two options: 1) Your F3 is fault...
by dknute
Mon Dec 17, 2012 1:25 pm
Forum: Troubleshooting
Topic: RPi doesn't boot after backpowering
Replies: 7
Views: 1212

Re: RPi doesn't boot after backpowering

You need to run a few more tests to pinpoint the problem. First, measure the resistance of the input polyfuse - with power disconnected of course. It should be less than 200 miliohms. Is it F3 that gets hot, or D17 diode maybe? Try to measure the voltage your power supply gives when not under load, ...
by dknute
Wed Dec 12, 2012 3:29 pm
Forum: Troubleshooting
Topic: Power, but no activity
Replies: 3
Views: 988

Re: Power, but no activity

What is "known good" in your case? Tested on another Pi? It's not unheard of for SD card to work in one device but not another. Do try another card with a fresh image of Raspbian or Arch.
by dknute
Wed Dec 12, 2012 3:25 pm
Forum: Troubleshooting
Topic: Hot Pi
Replies: 19
Views: 3369

Re: Hot Pi

Could you please elaborate on this bit: "tested the supply before the fuse and only gave1.9V"? It's too low for the PCB to work but too high to think the fuse has tripped. Somewhat weird in other words. IC2 might get somewhat hot but should not burn your fingers. It might be a problem with the Pi bu...
by dknute
Tue Dec 11, 2012 8:09 pm
Forum: Troubleshooting
Topic: Raspberry Pi Stuck at Raspberry Logo
Replies: 14
Views: 9577

Re: Raspberry Pi Stuck at Raspberry Logo

Actually, if you look at model A current draw, it looks like the USB+LAN chip does eat a lot. And from my own experience a switching regulator is not always stable even if you follow the recommended design guidelines. A bit of tweaking is sometimes required and this might only surface while doing lo...
by dknute
Thu Nov 29, 2012 11:57 pm
Forum: General discussion
Topic: Made in China & poor soldering
Replies: 53
Views: 7028

Re: Made in China & poor soldering

I have a temperature controlled Weller and I still find it a pain to remove solder from through holes. If your soldering station is 60W or higher then you should be able to do it. I just can't seem to stress enough the importance of proper tip for the job. You need something with nice, flat surface...
by dknute
Thu Nov 29, 2012 11:42 pm
Forum: General discussion
Topic: Naive question: Why have an sd card slot at all?
Replies: 25
Views: 8863

Re: Naive question: Why have an sd card slot at all?

If you doubt SD socket can take it then why are you advocating micro SD?
by dknute
Thu Nov 29, 2012 1:07 pm
Forum: General discussion
Topic: Temperature Sensor & Buzzer
Replies: 12
Views: 4596

Re: Temperature Sensor & Buzzer

Alfadaz, I think you're about to find out that 0.1 deg C precision comes with a price. Hefty one. The best approach would be to buy inexpensive I2C or SPI chip with good linearity and compensate for the initial offset and/or skew with one- or two-point manual calibration. Even that is much more prob...
by dknute
Thu Nov 29, 2012 10:29 am
Forum: Troubleshooting
Topic: Report: 3.6.7+ issues
Replies: 2
Views: 814

Re: Report: 3.6.7+ issues

More swapper: page allocation failures even with default clocking. This is the last straw I'm afraid, going back to 3.2.27+ now. I like this new CMA stuff and DVB-T drivers but unless my Pi actually survives the night it's not much of use.
by dknute
Wed Nov 28, 2012 9:50 pm
Forum: Troubleshooting
Topic: Report: 3.6.7+ issues
Replies: 2
Views: 814

Re: Report: 3.6.7+ issues

Same thing (page allocation failure) happened during another build run during the day, and this time it was the only task I started. Curiously the build took some 30min longer than usual but it finished successfully. Well I can't say much about the integrity of these files but there weren't any fata...
by dknute
Wed Nov 28, 2012 10:52 am
Forum: Troubleshooting
Topic: Pi wont boot without HDMI attached
Replies: 4
Views: 1188

Re: Pi wont boot without HDMI attached

That's an educated guess but I would assume HDMI detection code waits a bit to make sure the link is there (or not, as in this case) before defaulting to analog out. If you do have HDMI connected the wait is probaly shorter and the whole timing on the boot process is different.

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